Introduction
H56 is a brass alloy with approximately 56% copper (Cu) and 42–44% zinc (Zn). The designation "H56" is an industry convention based on nominal copper content — there is no unified international standard grade for this specific composition. Its properties and applications fall between low-copper brass and medium-copper brass, making it a balanced, cost-effective choice for general hardware and mechanical components.
H56 belongs to the alpha-beta (α+β) two-phase brass family. Compared to higher-copper grades such as H62, H56 has higher zinc content, resulting in greater strength and hardness but slightly reduced ductility and corrosion resistance. Compared to C3604 free-cutting brass, H56 has lower lead content and is not optimized for high-speed automatic lathe machining.
Content authorized for publication by FULLERKREG.
Chemical Composition
| Grade | Cu (%) | Zn (%) | Pb (%) | Fe (%) |
|---|---|---|---|---|
| H56 | 55–57 | 42–44 | ≤ 0.30 | ≤ 0.10 |
Notes on composition:
- Lead (Pb, ≤ 0.30%): Present as a controlled impurity (not intentionally added at free-machining levels). Trace Pb improves machinability to a limited degree.
- Iron (Fe, ≤ 0.10%): Minor addition that slightly improves heat resistance and grain refinement.
- No unified international standard: H56 is an industry trade designation. Buyers should confirm composition with suppliers. Approximate ASTM equivalents fall in the C27400–C28000 range (Muntz Metal family).
Mechanical Properties
| Property | Value |
|---|---|
| Tensile Strength | 400–480 MPa |
| Yield Strength | 350–400 MPa |
| Elongation (δ10) | 5–15% |
| Hardness | 100–130 HB |
Physical Properties
| Property | Value |
|---|---|
| Density | 8.4–8.5 g/cm³ |
| Melting Point | 900–940 °C |
| Thermal Conductivity | 120–150 W/(m·K) |
| Electrical Conductivity | 15–20 %IACS |
| Thermal Expansion (20–100°C) | 18–20 × 10⁻⁶ /°C |
| Elastic Modulus | 90–95 GPa |
Brass Grade Comparison
| Grade | Cu (%) | Zn (%) | Strength | Ductility | Machinability | Typical Use |
|---|---|---|---|---|---|---|
| H56 | 55–57 | 42–44 | Medium-High | Moderate | Good | General hardware, fittings, low-cost parts |
| H62 | 60.5–63.5 | Balance | Medium | Good | Good | Hardware, stampings, mechanical parts |
| C3604 | 57–61 | Balance | Medium | Good | Excellent (free-machining) | CNC turning, automatic lathe precision parts |
Applications of H56 Brass
H56 is suited for applications where moderate performance and cost-effectiveness are the priority:
- Hardware fittings — general-purpose hardware, brackets, clips, and connectors
- Pipe & plumbing components — pipe fittings, valve bodies, and adapters in non-aggressive environments
- Decorative items — ornamental hardware, jewelry findings, and decorative trim
- Furniture & architectural hardware — handles, hinges, and decorative fittings
- Electronics & electrical — terminals, connectors, and contact components
- Mechanical manufacturing — medium-complexity cold-formed parts produced in high volumes
Fabrication Characteristics
Cold Working
H56 performs well in cold working operations including stamping, bending, and drawing. In the annealed condition, plasticity is adequate for moderate forming. Work hardening is pronounced — intermediate annealing is required for multi-stage forming operations to restore ductility.
Hot Working
Hot working should be performed in the 700–850°C range. Temperatures above this range risk zinc volatilization (zinc burn-off), which degrades surface quality and composition. The α+β two-phase structure provides good hot workability for forging and extrusion within this window.
Machinability
H56 has good machinability — chips break cleanly and surface finish is good. It is suitable for drilling, turning, and milling of medium-complexity parts in batch production. For high-speed automatic lathe operations requiring maximum machinability, C3604 free-cutting brass remains the preferred choice.
Weldability
H56 has moderate weldability. Threaded connections and brazing are preferred over fusion welding, which risks zinc volatilization and porosity. Silver-based or copper-phosphorus brazing alloys are recommended for joining.
Corrosion Resistance
H56 offers moderate corrosion resistance suitable for atmospheric and fresh water environments. In humid, saline, or marine environments, mild surface oxidation may occur over time. For marine-grade applications, higher-copper alloys or specialized marine brass grades are recommended. Surface treatments such as lacquering or plating can extend service life in corrosive conditions.
Note: H56 is an industry trade designation without a unified international standard. Approximate ASTM equivalents: C27400–C28000 (Muntz Metal family). Always confirm composition with your supplier.
Content authorized for publication by FULLERKREG.